#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
char repeatedCharacter(char* s) {
    int len = strlen(s);
    if (len == 1)
        return s;
    int i = 0;
    char c[26] = { 0 };
    for (i = 0; i < len; i++)
    {
        c[s[i] - 'a']++;
        if (c[s[i] - 'a'] == 2)
            return s[i];
    }
    return s[i];
}
int main()
{

	return 0;
}